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hard crash despite UPS



My UPS, an APC BackUPS 650, seems ineffective under Linux.  Originally
I thought this was because it could not cope with the load, but it
works OK under MS-Windows.

That is, when I pull the cord from the wall under Windows I get an
alert the UPS is on battery.  When I do the same under Linux, the
system powers off immediately (not a controlled shutdown).

I use the apcupsd on a woody system with 2.4.19 kernel.  Suspecting a
configuration problem, I reviewed my settings with APC tech support,
but this didn't help.  I also tried disabling the demon before pulling
the plug; this didn't help.  I think this kills the theory that it is
a problem with apcupsd.

I do notice that I get the error message
LSR safety check engaged
on ttyS1 whenever I run the apcupsd demon (as well as on system start
up).  I see in the newsgroups this is a sign that something is wrong
with the serial driver, but I'm not sure what. ttyS1 is where the UPS
communicates.


Hmm, I suppose a further test would be to disconnect the serial cable
and see if this makes a difference.

Anyway, I'm at a bit of a loss to track this problem down, and would
appreciate any assistance.  Some theories, none compelling, that occur
to me: 

1) Something else is watching ttyS1 and causing the shutdown.  (What?)

2) The UPS detects that communication has failed and shuts down.  The
problem with this theory is that the UPS uses simple (dumb) signalling:
messages only go from the UPS to the computer. So there doesn't seem
to be anyway the UPS would even know there was a problem.

3) The system draws more power under Linux than Windows 2000, and this
is just enough to put the battery over the edge.  This assumes
something else is weakening the battery, because it nominally clearly
has enough juice.  However, my utility power is pretty poor, and this
could strain the system.

4) apcupsd is still hanging around despite /etc/init.d/apcupsd stop,
and it's still the culprit. (I can try removing the package).

Some possibly relevant log entries (gaps indicate omissions):
Jan 22 14:25:48 wheat kernel: Serial driver version 5.05c (2001-07-08) with MANY_PORTS SHARE_IRQ SERIAL_PCI ISAPNP enabled
Jan 22 14:25:48 wheat kernel: ttyS00 at 0x03f8 (irq = 4) is a 16550A
Jan 22 14:25:48 wheat kernel: ttyS02 at 0x03e8 (irq = 4) is a 16550A
Jan 22 14:25:48 wheat kernel: ttyS01 at port 0x02f8 (irq = 3) is a 16550A

Jan 22 14:25:48 wheat kernel: eth0: Setting 100mbps full-duplex based on auto-negotiated partner ability 41e1.
Jan 22 14:25:48 wheat kernel: ttyS1: LSR safety check engaged!
Jan 22 14:25:48 wheat last message repeated 2 times

Jan 22 14:25:49 wheat kernel: ttyS1: LSR safety check engaged!
Jan 22 14:25:49 wheat apcupsd[396]: apcupsd 3.8.5 (4 January 2002)
debian startup succeeded

There are no log entries from the time of the crash.

genpower was on my system, but I removed it.
acpid is installed



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